A video uploaded to YouTube captured shoppers fighting over a crate of mobile phones at Walmart in Moultrie, Georgia.

It quickly became an online hit after being posted on news websites around the US, with 1.9 million views on Monday morning.

Perhaps anticipating the chaos, many shoppers preferred to buy online – even ahead of the next nationwide shopping event, Cyber Monday.

Reuters reported Black Friday online sales topped $US1 billion for the first time, according to digital analytics company comScore Inc.

IBM said online sales rose 16.9 per cent year-on-year on Saturday.

Some bricks-and-mortar stores opened at midnight, while others such as retailers Walmart and Target jumped the gun, opening on Thanksgiving night and carving into the family-centred holiday.

But the day's impact on balance sheets is starting to wane, as more stores try to reel-in customers on Thursday, even if it means that their employees have to forego the traditional Thanksgiving feast.

A decade ago, it would have been impossible to find a single store open on Thanksgiving along New York's big shopping arteries such as Broadway.

But on Thursday, as for the past several years, nearly all the stores were open where Broadway traverses the SoHo neighbourhood of lower Manhattan.

Walmart, the world's biggest retailer, said it had its "best ever" Black Friday, with larger crowds than last year.

Meanwhile, disgruntled Walmart workers mounted strikes and protests across the country seeking better pay and benefits.

"There is going to be an impact," employee William Fletcher told MSNBC. "The point isn't so much to hurt Walmart as much as it is to get them to listen to us and appreciate the work we do."

The next in a series of days that stores are counting on to jumpstart the holiday shopping season is Cyber Monday.

Cyber Monday was created in 2005 by a shopping trade group that noticed online sales spiked on the Monday following Thanksgiving.

It's estimated that this year's event will be the biggest online shopping day of the year for the third year in a row.

According to comScore, Americans are expected to spend $1.5 billion, up 20 per cent from last year on Cyber Monday, as retailers have ramped up their deals to get shoppers to click on their websites.

Amazon.com, which is starting its Cyber Monday deals at midnight on Monday, is offering as much as 60 per cent off a Panasonic VIERA 55-inch TV that's usually priced higher than $1000 ($956). Sears is offering $430 ($411) off a Maytag washer and dryer, each on sale for $399 ($381). And Kmart is offering 75 per cent off all of its diamond earrings and $60 ($57) off a 12-in-1 multigame table, on sale for $89.99 ($86).